by Oren Dorell, USA TODAY

by Oren Dorell, USA TODAY

Israel's ground offensive in the northern end of the Gaza Strip may require a week or more to destroy tunnels and rocket launchers used by Hamas militants to attack Israel.

"To occupy this area it's a matter of one day," Retired Maj. Gen. Shlomo Brom, former director of the Strategic Planning Division of the General Staff of the Israel Defense Forces, said Friday, a day after Israeli troops launched the offensive. "Then it takes time to clear the area. Searching can take a week or two."

The Israelis have one advantage they lacked in 2012, when they last engaged in major hostilities with Hamas: a government in Egypt that has been combating the militant group. Two years ago, Egypt's president, Mohammed Morsi, belonged to the Muslim Brotherhood. And Hamas is the Palestinian branch of the Islamist group.

Now, however, Morsi has been ousted and imprisoned by a military-run government that has been conducting operations to eliminate hundreds of Hamas tunnels along Egypt's border with the Gaza Strip to stem the flow of weapons to an Islamist insurgency in the Sinai Peninsula.

As the operation continues, Palestinian casualties that include many civilians will continue to mount, prompting world leaders to pressure Israel to end its offensive. That could complicate Israel's aim to stay in Gaza until Hamas accepts a cease-fire. Brom says Israel "may stay there to put pressure on Hamas to accept a ceasefire," which could take longer than Israel needs to accomplish the military aim of its offensive.

The Palestinian death toll from the offensive rose to more than 300 on Saturday, according to the Associated Press.

As Israel reported its first military casualty in the offensive, apparently from friendly fire, Prime Minister Benjamin Netanyahu said the operation is aimed at eliminating tunnels that Palestinian militants tried to use twice in recent days to attack Israeli civilians, and to end the rocket fire that prompted the operation to begin with.

"Since there is no way to deal with the tunnels only from the air, our soldiers are doing it now from the ground," Netanyahu said Friday at an emergency cabinet meeting in Tel Aviv.

Netanyahu told his military to prepare to expand the ground operation, which he launched after Hamas refused an Egyptian cease-fire proposal this week and continued to launch rockets at Israeli communities.

Hamas has said it would agree to a 10-year cease-fire if Israel and Egypt meet its demands: Open the Rafah crossing between Gaza and Egypt, pay its 40,000 government workers, remove Israeli tanks from the Gaza border, allow Palestinian farmers to work their lands along the Israeli border, and release Palestinian prisoners.

Israel released hundreds of prisoners in 2011 for the return of abducted Israeli soldier Gilad Shalit. But last month, it rounded up many of them in the search for three Israeli teenage settlers who were kidnapped in the West Bank and found murdered in early July.

A revenge killing of a Palestinian teenager and subsequent rioting by Arabs in East Jerusalem precipitated the latest conflict.

Israel launched the ground offensive after 10 to 12 militants entered Israel Thursday through a tunnel near Kibbutz Sufa. The gunmen, who carried RPGs, grenades and assault rifles, were spotted and killed before they reached the community.

Israel's military says it found eight tunnels since the operation began, Israeli news site Ynet News reported.

Israel has been targeting tunnels, which Hamas says it has dug to ambush Israeli soldiers should they invade, and which it has used in the past to launch attacks and to abduct Shalit in 2006.

Several Hamas militants were killed on July 6 while handling explosives in a tunnel that Israel said the militants planned to use to sneak into Israel for an attack. And four militants were killed July 9 after swimming ashore and firing on Israeli forces.

Getting rid of the tunnels will be easier then ending all the rocket fire from Gaza. That goal would require re-occupying the entire territory Israel vacated in 2006 and again provide services and security to all 2 million residents amid continued fighting, Brom said.

Israel seems prepared to take the northern portion of Gaza, where Hamas positioned the majority of its longer-range rockets that targeted Israel's northern cities.

Egypt, under its new president, former Gen. Abdel-Fattah El-Sisi, is more determined to stop smuggling than in 2012, when Morsi brokered a cease-fire with Hamas. Egypt again is trying to broker a truce, though now with a less friendly Hamas.

"Clearing the whole Strip would take years," Brom said. To eliminate all the rockets would be such a task that "the cure is worse than the disease."